The primary suspect is generally your resume. It is important to pay attention to how adapted your resume is to the job description. In general, nobody wants to receive the resume of a medical doctor for a role that asks for a lawyer. The responsibility of adapting your resume lies solely with you because the person reviewing your cv might not be interested in making direct correlations on your behalf. In a nutshell, ensure that your resume is dummy-proof and that it tells a clear and consistent story so that the person reading your resume can directly correlate all of the information presented there to the requirements of the role that you have applied to. It is also important to do away with internal job titles; so for example, if the role of the Tech lead is internally called a chief whip, what should be on your resume should be tech lead and not chief whip because that is the title that is recognized by the job market. Using market recognisable names would make your resume more understandable.